Collect 24-hour urine. Refrigerate during collection. Also acceptable: Random urine.
Adjust pH to less than or equal to 2 by adding 6M HCl. Transfer a 4 mL aliquot of urine to a Standard Transport Tube. (Min: 0.5 mL) Record total volume, collection time interval, and pH on transport tube and test request form. Also acceptable: Specimens previously preserved with boric acid.
Storage/Transport Temperature: Refrigerated
For sites that do not have access to HCl, the urine can be poured off into a sage cup and sent to Marshfield Labs at refrigerated temperatures for preservation prior to submission to ARUP.